Messages in this thread | | | From | Will Deacon <> | Subject | [PATCH v2 0/6] Rework REFCOUNT_FULL using atomic_fetch_* operations | Date | Tue, 27 Aug 2019 17:31:58 +0100 |
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Hi all,
This is version two of the patches I previously posted here:
https://lkml.kernel.org/r/20190802101000.12958-1-will@kernel.org
Changes since v1 include:
* Avoid duplicate WARNs when incrementing from zero * Some crude lktdm perf results to motivate the change:
# perf stat -r 3 -B -- echo {ATOMIC,REFCOUNT}_TIMING >/sys/kernel/debug/provoke-crash/DIRECT
# arm64 ATOMIC_TIMING: 46.50451 +- 0.00134 seconds time elapsed ( +- 0.00% ) REFCOUNT_TIMING (REFCOUNT_FULL, mainline): 77.57522 +- 0.00982 seconds time elapsed ( +- 0.01% ) REFCOUNT_TIMING (REFCOUNT_FULL, this series): 48.7181 +- 0.0256 seconds time elapsed ( +- 0.05% )
# x86 ATOMIC_TIMING: 31.6225 +- 0.0776 seconds time elapsed ( +- 0.25% ) REFCOUNT_TIMING (!REFCOUNT_FULL, mainline/x86 asm): 31.6689 +- 0.0901 seconds time elapsed ( +- 0.28% ) REFCOUNT_TIMING (REFCOUNT_FULL, mainline): 53.203 +- 0.138 seconds time elapsed ( +- 0.26% ) REFCOUNT_TIMING (REFCOUNT_FULL, this series): 31.7408 +- 0.0486 seconds time elapsed ( +- 0.15% )
Cheers,
Will
Cc: Kees Cook <keescook@chromium.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Elena Reshetova <elena.reshetova@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Hanjun Guo <guohanjun@huawei.com> Cc: Jan Glauber <jglauber@marvell.com>
--->8
Will Deacon (6): lib/refcount: Define constants for saturation and max refcount values lib/refcount: Ensure integer operands are treated as signed lib/refcount: Remove unused refcount_*_checked() variants lib/refcount: Move bulk of REFCOUNT_FULL implementation into header lib/refcount: Improve performance of generic REFCOUNT_FULL code lib/refcount: Consolidate REFCOUNT_{MAX,SATURATED} definitions
drivers/misc/lkdtm/refcount.c | 8 -- include/linux/refcount.h | 236 +++++++++++++++++++++++++++++++++++++---- lib/refcount.c | 237 +----------------------------------------- 3 files changed, 218 insertions(+), 263 deletions(-)
-- 2.11.0
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